A valve of this kind is used in the paintball gun of our co-pending United States Patent Applications one of which is Ser. No. 10/775,756 and was filed on Feb. 9, 2004 and the other of which is Ser. No. 10/870,687 and was filed on Jun. 17, 2004. In those Applications the valve is used to communicate a source of compressed air with a chamber in which it is stored prior to being released through the bolt of the gun. When the gun is fired the valve serves to isolate the chamber from the source so that only the air stored in the chamber is used to fire a paintball.
In any pneumatic or hydraulic system using telescopic components it is necessary to provide O-ring seals in respective circumferential grooves on opposite sides of an opening in one of the components communicating with the source of compressed fluid if that opening is to be successfully occluded by the other component in the closed position of the valve. In the absence of such seals the compressed fluid may escape between the components.
According to the proposals of our said co-pending patent applications one of the O-ring seals on opposite sides of a bore communicating with a canister of compressed air must pass to or beyond the circumferential depression in the outer periphery of the bolt in order to communicate the bore with the interior of the storage chamber. The system works quite well but there is a danger that the said one O-ring may become deformed when it is aligned with the depression and therefore unsupported by the periphery of the bolt. The pressurised air entering the groove of the said O-ring may tend to displace it. Thus when the bolt moves back from its firing position the deformed or displaced O-ring may jam in the depression causing the mechanism to “lock up”.
A principal object of the present invention is to offer a solution to this problem.